Digital multimeters (DMM) and digital voltmeters (DMV) are commonly used in conjunction with test and measurement instruments, probes, and accessories. The test and measurement instrument may be an oscilloscope, for example. An oscilloscope provides a visual picture in time of how a circuit is performing. Traditionally, with oscilloscopes, the accuracy and resolution of a voltage measurement is limited and is typically a ground referenced measurement. DMMs and DVMs, on the other hand, can provide extremely accurate, high resolution measurements that are galvanically isolated, also known as “floating,” from earth ground.
Past attempts have been made to incorporate DMM and DMV measurements into oscilloscopes to obtain an accurate voltage measurement. These attempts, however, have been limited by requiring an additional set of probes to be connected to the device under test or integrating the DVM feature into the oscilloscope itself that is ground referenced and is limited in sensitivity and accuracy by the traditional oscilloscope probe connected to the oscilloscope.
Combining DMM-like and DMV-like measurement capabilities with a traditional oscilloscope voltage probe that is galvanically isolated from earth ground would overcome the limitations of the past and provide an easy to use solution. This would be particularly useful for users making non-ground referenced, or “floating,” voltage measurements.